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## Homework Statement

A sled weighing 70kg, going at 14 m/s, slides down a ramp 3 m high. It's final velocity is 15.6 m/s. How much energy was lost due to friction?

## Homework Equations

.5mv

_{i}

^{2}+ mgh = .5mv

_{f}

^{2}+ x

where x = joules of energy for friction

## The Attempt at a Solution

step 1 .5(70)(14

^{2}+70(9.8)(3) = .5(70)(15.6

^{2}+ x

step 2 6860 + 2058 = 8570 + x

step 3 6860 + 2058 - 8570 = x

step 4 401 = x

The books says the answer is 74